For some, the internet is merely a hiding place — a web of secret corridors where all manner of shameful deeds unfold. But the police never expected that it might become a strategic platform where two groups of society's outcasts, terrorists and child sex abusers, could meet to exchange operational secrets. The realisation that there might be something in common between violent Muslim fanatics known for their supposed piety and sexual deviants who prey on children has only slowly dawned on officers. Cracking the mystery of how these worlds overlap is expected to improve understanding of the mindsets of both...